Chop a string in Ruby into fixed length string ignoring (not considering/regardless) new line or space characters

"This is some\nText\nThis is some text".scan(/.{1,17}/m)
# => ["This is some\nText", "\nThis is some tex", "t"]

Yet another way:

(0..(a.length / 17)).map{|i| a[i * 17,17] }
#=> ["This is some\nText", "\nThis is some tex", "t"]

Update

And benchmarking:

require 'benchmark'
a = "This is some\nText\nThis is some text" * 1000
n = 100

Benchmark.bm do |x|
  x.report("slice") { n.times do ; (0..(a.length / 17)).map{|i| a[i * 17,17] } ; end}
  x.report("regex") { n.times do ; a.scan(/.{1,17}/m) ; end}
  x.report("eachc") { n.times do ; a.each_char.each_slice(17).map(&:join) ; end }
end

result:

         user     system      total        real
slice  0.090000   0.000000   0.090000 (  0.091065)
regex  0.230000   0.000000   0.230000 (  0.233831)
eachc  1.420000   0.010000   1.430000 (  1.442033)